Angular distribution for electron capture by protons from hydrogen atoms in the energy range 15-200 keV

Several authors have, using a variety of approximations, predicted a sharp minimum in the angular distribution for the process p+H(1s)→H(1s)+p, over a wide range of energies. I have used the results of recent impact-parameter coupled-state calculations, in conjunction with the eikonal approximation, to calculate differential cross sections for this process in the energy range 15-200 keV; no sharp minima were found, but at the lowest end of the energy range there is some indication of the emergence of a dip. The present results are qualitatively consistent with the results of Glembocki and Halpern who used a Coulomb-projected Born approximation.